¹⁴⁷sm-¹⁴³Nd and ⁸⁷Rb-⁸⁷Sr ages of the eucrite Piplia Kalan

Abstract

Prompted by the finding that the eucrite Piplia Kalan could have retained Pu fission Xe earlier than the eucrites so far studied and hence be very ancient, we have measured a precise internal ¹⁴⁷Sm-¹⁴³Nd isochron for this meteorite. The age and initial Nd ratio relative to CHUR are 4.570 ± 0.023 Ga and -1.3 ± 0.7 ευ, respectively. A Rb-Sr whole rock (clast) isochron for this meteorite corresponds to an age of 3.963 ± 0.119 Ga and initial ⁸⁷Sr/⁸⁶Sr ratio of 0.69902 ± 3. But initial ⁸⁷Sr/⁸⁶Sr ratio calculated for an age of 4.57 Ga is 0.698956 ± 25, which is indistinguishable from 0.698970 ± 15 reported for the angrites LEW and ADOR dated at 4.5578 ± 0.0005 Ga. These results indicating that Piplia Kalan could have formed within only a few million years of the earliest condensates in the Solar System are strongly supported by the recent discovery of live ²⁶Al in it.